Ink distributing means comprising a bundle of skewed rollers

ABSTRACT

Ink distributing means for a printing press comprising a bundle of rollers, each contacting two other rollers. The axes of said rollers are displaced to form a twisted bundle. The surfaces of two of the rollers are elastic to accommodate the displacements of the axes and make good contact along the lengths of said rollers.

United States Patent Harrison Aug. 29, 1972 [54] INK DISTRIBUTING MEANS538,985 5/1895 Turley ..101/187 COMPRISING A BUNDLE OF SKEWED 1,840,0091/ 1932 Ball et a1 ..l0l/350 ROLLERS 3,366,047 1/1968 Hermach et al...l01/216 3,433,155 3/1969 Norton ..l01/148 [72] Invent g z 55 Valley3,094,065 6/1963 Roberts ..l01/148 7 3,131,629 5/1964 Barnes ..101/148Assignee: Instrument Co. Inc. Glen Dahlgren l Head NY. 3,208,377 9/1965l-lantscho ..l01/352 [22] Filed: July 16, 1970 Primary Examiner-J. ReedFisher Assistant Examiner-C. W. l-lanor [21] Appl' 55496 Att0mey.lamesP. Malone [52] US. Cl ..l01/350 [57] ABSTRACT [51] Int. Cl. ..B4lf1/46,B41f3l/4l [58] Field of Search ..172/34s-352, 205-208, Ink dsmbumg meansprmimg Press compnsmg 172/148 a bundle of rollers, each contacting twoother rollers. The axes of said rollers are displaced to form a twistedbundle. The surfaces of two of the rollers are elastic to [56]References Clted accommodate the displacements of the axes and makeUNITED STATES PATENTS good contact along the lengths of said rollers.

1,995,701 .3/1935 Buttner ..101/350 3 Claims, 3 Drawing Figures2,762,295 9/1956 Varga et al. ..l01/148 X 1,755,278 4/1930 Strain....10l/348 1,733,716 10/1929 Black ..101/350 ZONEI ZON p'Ati'mEmuszsI872 3.6 737 9 INVENTOR.

' FIG 2A BY HENRY HARRISON INK DISTRIBUTING MEANS COMPRISING A BUNDLE FSKEWED ROLLERS This invention relates to ink distributing roller means.More particularly, the invention provides new and improved inkdistributing roller means which eliminate the need for axially movingone or more of the ink feed rollers.

It is common practice in printing machines to provide at least oneroller in the train of ink rollers, which reciprocates in an axialdirection while it turns. This roller, commonly called the vibratoryroller or vibrator, maintains a uniform or graded thickness of inkacross the lateral dimension of the press. Without a vibrator, the inkdistribution becomes thin in bands where image areas deplete it andbecomes thick in the non-image areas. The boundaries between thick andthin areas become sharply defined, resulting in very noticeablevariations of density in the printed image. This is sometimes calledghosting.

Various means have been employed to impart axial vibratory motion androtary motion simultaneously to a vibrator roller. All are intermittentin operation, introducing undesired dynamic forces and reducedefficiency of operation. All are mechanically complex, requiring a camor crank driving device and special bearings. These mechanisms,introduce cost and wear problems.

Accordingly, it is a primary object of this invention to provide aroller means for distributing ink laterally in a continuous fashionemploying rotary motion only, without axial reciprocation or rotation.By this simplification the cost of a machine will be significantlyreduced and the efficiency of uniforming the ink will be improved.

Another object of the invention is to provide new and improved inkfeeding means for printing presses.

Another object of the invention is to provide new and improved inkfeeding means forprinting presses comprising a bundle of feed rollers,at least four in number, each roller contacting two other rollers, theaxes of said rollers being displaced to form a twisted bundle.

These and other objects of the invention will be apparent from thefollowing specification and drawings of which:

FIG. 1 is a perspective view of an embodiment of the invention.

FIG. 2 is an enlarged perspective view of the twisted I bundle ofrollers illustrating the operation of the inventron.

FIG. 2A is an end view of FIG. 2.

FIG. 1 shows a typical arrangement of ink rollers. Ink is transferredfrom the slow-turning ink fountain roller 1 1 to the ductor roller 12,which intermittently touches a hard-surfaced idler roller A, turning atpress speed. This hard surface idler A makes contact with a pair ofelastic-surfaced rollers B and C which convey ink to a hard surfaceddistributor roller D geared to turn at press speed. This distributor Droller drives the idler roller system. From the distributor roller twoidling elastic-surfaced form rollers E and F transfer ink to the surfaceof the type or plate roller G image areas, and from there it goes to thesurface being printed directly, in letterpress machines, or via anoffset blanket in offset machines. Rollers B and C are skewed in thesame direction with respect to roller A. Roller D is additionally skewedin the same direction with respect to rollers B and C. Rollers A, B, Cand D comprise a twisted bundle.

In conventional printing machines either the hardsurfaced idler roller Aor the distributor roller D or both would have reciprocating axialmotion as well as rotation, to smooth irregularities of ink thicknessacross the width of the roller system.

In the present invention, both the hard surface distributor D and thehard surface idler A, and also the two elastic-surfaced rollers B and Cbetween them, rotate without axial motion, at press speed in constantcontact with each other, but the axesof the four rollers are notparallel to each other.

How this roller system works to smooth irregularities of ink thicknessacross the width of the roller system can be understood from FIG. 2.

Suppose an irregularity in the ink film thickness on roller A exists inthe first zone. This irregularity comes in contact with roller B atcontact point l, with roller C at point 2, with roller C at point 3, andagain with roller A at point 4. But point 4 is in a second zone,displaced from the first zone where the irregularity was first assumedto be. Thus the ink film thickness in the first zone is averaged withthe thickness in the second zone. At the same time, an irregularity inzone 2 would travel to a third zone on beyond it and so on over thewhole width of the roller system.

An exchange process where an irregularity passes from contact 1 tocontact 2 to contact 3 to contact 4 has been described. Withoutreversing the rotation of the rollers, a reverse exchange also takesplace, bringing an irregularity at contact 4 around the outside ofroller D to contact 3, around the inside of roller C to contact 2,around the outside of roller B to contact 1. Thus an irregularity inzone 1 continuously exchanges or averages not only with zone 2 but alsowith another zone on the opposite side of zone 1.

Theoretically all these rollers should be hyperboloids of one sheet, butin practice the angle between axes of rotation is so small thatcylindrical elastic-surface rollers easily compress to make good contactover their entire length. An angle of about 2 between successive axeshas been found to give good results. The number of rollers in thetwisted group exchanging can be any even number greater than or equal tofour. The hand of the twist of the roller axes or of rotation of thedistributor roller, for example, have no effect on the exchange process,which takes place equally in both directions. The angle of twistdetermines the distance between exchange zones on any particular roller,which is related to the rate at which a lateral unevenness of the inkfilm is averaged out.

FIG. 2A shows an end view of FIG. 2.

The invention is not limited to printing presses, but has applicationwherein a liquid is being fed by rollers, for instance in chemicalprocessing machines.

Uniforming action takes place whenever the rollers contact each other ina complete sequence. In cases where constant uniforming action is notrequired, one of the chain of rollers may be a ductor makingintermittent contact. Lateral irregularities in the ink film whichdevelop while the ductor is in contact with the fountain roller aresmoothed out while the ductor is in contact with distributor rollers,completing the twisted bundle.

Similarly, where a bare minimum number of ink rollers is a primaryconsideration, a form roller may be included in the twisted group ofrollers.

I claim:

1. A roller system for distributing a viscous material including aninput roller means for supplying ink to said input roller, twointermediate rollers and an output roller, each intermediate rollerbeing mounted in rolling contact with said input and output rollers,means fixing the axis of each intermediate roller in a skewed positionwith respect to the input roller, and means locating the axis of theoutput roller in a skewed direction with respect to said intermediaterollers, said direction of skew being the same as the axis of each ofsaid intermediate rollers, whereby an irregularity in ink film thicknesson said input roller is averaged along its length.

2. Apparatus as in claim 1 wherein the axes of contacting rollers aredisplaced, 2.

3. Apparatus as in claim 1 wherein said input and output rollers of saidfour rollers have a harder surface than said intermediate rollers, andsaid intermediate rollers have elastic surfaces to provide continuouscontact along their length.

1. A roller system for distributing a viscous material including aninput roller, means for supplying ink to said input roller, twointermediate rollers and an output roller, each intermediate rollerbeing mounted in rolling contact with said input and output rollers,means fixing the axis of each intermediate roller in a skewed positionwith respect to the input roller, and means locating the axis of theoutput roller in a skewed direction with respect to said intermediaterollers, said direction of skew being the same as the axis of each ofsaid intermediate rollers, whereby an irregularity in ink film thicknesson said input roller is averaged along its length.
 2. Apparatus as inclaim 1 wherein the axes of contacting rollers are displaced, 2*. 3.Apparatus as in claim 1 wherein said input and output rollers of saidfour rollers have a harder surface than said intermediate rollers, andsaid intermediate rollers have elastic surfaces to provide continuouscontact along their length.